Deformation microstructure and properties control of Cu-0.6Cr alloy in cryo-equal channel angular pressing

Abstract

Cu-0.6Cr alloy was extruded by liquid nitrogen cooling equal channel angular pressing (ECAP) route-Bc and aging treated at 400 °C–500 °C; the structure and orientation distribution of the alloy were detected by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), electron back-scattered diffraction (EBSD) and TEM. The purpose is to detect the influence of deformation conditions and aging treatment on the microstructure and properties of the materials, and to analyzed the microscopic mechanism of the precipitates formation process and transformation. The results show that the cryo-ECAP-Bc deformation will accelerate the interaction between the microstructure and texture of the Cu-0.6Cr alloy, and reduce the limitation size of the grains after deformation. Strain increase can promote increasing the amounts of micro/nano precipitates discontinuous distribution on the grain boundaries. After 4 passes of extrusion and aging at 450 °C, the tensile strength, hardness and elongation of the material reach to 555.0 MPa, HV 167.3 and 13.1%, respectively, and the conductivity exceeds 84%IACS. The synergistic effect of microalloying, solid solution, cryo-ECAP and aging, and the formation of {111} <112> and {111} <110> textures are beneficial to improving the conductivity of the alloy simultaneously.

Keywords

equal channel angular pressing / Cu-0.6Cr alloy / aging / texture

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